PCI trouble on mvebu (Turris Omnia)

[Rob Herring]

On Wed, Oct 28, 2020 at 10:08 AM Toke Høiland-Jørgensen <toke at redhat.com> wrote:
>
> Bjorn Helgaas <helgaas at kernel.org> writes:
>
> > On Wed, Oct 28, 2020 at 02:36:13PM +0100, Toke Høiland-Jørgensen wrote:
> >> Toke Høiland-Jørgensen <toke at redhat.com> writes:
> >>
> >> > Bjorn Helgaas <helgaas at kernel.org> writes:
> >> >
> >> >> [+cc vtolkm]
> >> >>
> >> >> On Tue, Oct 27, 2020 at 04:43:20PM +0100, Toke Høiland-Jørgensen wrote:
> >> >>> Hi everyone
> >> >>>
> >> >>> I'm trying to get a mainline kernel to run on my Turris Omnia, and am
> >> >>> having some trouble getting the PCI bus to work correctly. Specifically,
> >> >>> I'm running a 5.10-rc1 kernel (torvalds/master as of this moment), with
> >> >>> the resource request fix[0] applied on top.
> >> >>>
> >> >>> The kernel boots fine, and the patch in [0] makes the PCI devices show
> >> >>> up. But I'm still getting initialisation errors like these:
> >> >>>
> >> >>> [    1.632709] pci 0000:01:00.0: BAR 0: error updating (0xe0000004 != 0xffffffff)
> >> >>> [    1.632714] pci 0000:01:00.0: BAR 0: error updating (high 0x000000 != 0xffffffff)
> >> >>> [    1.632745] pci 0000:02:00.0: BAR 0: error updating (0xe0200004 != 0xffffffff)
> >> >>> [    1.632750] pci 0000:02:00.0: BAR 0: error updating (high 0x000000 != 0xffffffff)
> >> >>>
> >> >>> and the WiFi drivers fail to initialise with what appears to me to be
> >> >>> errors related to the bus rather than to the drivers themselves:
> >> >>>
> >> >>> [    3.509878] ath: phy0: Mac Chip Rev 0xfffc0.f is not supported by this driver
> >> >>> [    3.517049] ath: phy0: Unable to initialize hardware; initialization status: -95
> >> >>> [    3.524473] ath9k 0000:01:00.0: Failed to initialize device
> >> >>> [    3.530081] ath9k: probe of 0000:01:00.0 failed with error -95
> >> >>> [    3.536012] ath10k_pci 0000:02:00.0: of_irq_parse_pci: failed with rc=134
> >> >>> [    3.543049] pci 0000:00:02.0: enabling device (0140 -> 0142)
> >> >>> [    3.548735] ath10k_pci 0000:02:00.0: can't change power state from D3hot to D0 (config space inaccessible)
> >> >>> [    3.588592] ath10k_pci 0000:02:00.0: failed to wake up device : -110
> >> >>> [    3.595098] ath10k_pci: probe of 0000:02:00.0 failed with error -110
> >> >>>
> >> >>> lspci looks OK, though:
> >> >>>
> >> >>> # lspci
> >> >>> 00:01.0 PCI bridge: Marvell Technology Group Ltd. Device 6820 (rev 04)
> >> >>> 00:02.0 PCI bridge: Marvell Technology Group Ltd. Device 6820 (rev 04)
> >> >>> 00:03.0 PCI bridge: Marvell Technology Group Ltd. Device 6820 (rev 04)
> >> >>> 01:00.0 Network controller: Qualcomm Atheros AR9287 Wireless Network Adapter (PCI-Express) (rev 01)
> >> >>> 02:00.0 Network controller: Qualcomm Atheros QCA986x/988x 802.11ac Wireless Network Adapter (rev ff)
> >> >>>
> >> >>> Does anyone have any clue what could be going on here? Is this a bug, or
> >> >>> did I miss something in my config or other initialisation? I've tried
> >> >>> with both the stock u-boot distributed with the board, and with an
> >> >>> upstream u-boot from latest master; doesn't seem to make any different.
> >> >>
> >> >> Can you try turning off CONFIG_PCIEASPM?  We had a similar recent
> >> >> report at https://bugzilla.kernel.org/show_bug.cgi?id=209833 but I
> >> >> don't think we have a fix yet.
> >> >
> >> > Yes! Turning that off does indeed help! Thanks a bunch :)
> >> >
> >> > You mention that bisecting this would be helpful - I can try that
> >> > tomorrow; any idea when this was last working?
> >>
> >> OK, so I tried to bisect this, but, erm, I couldn't find a working
> >> revision to start from? I went all the way back to 4.10 (which is the
> >> first version to include the device tree file for the Omnia), and even
> >> on that, the wireless cards were failing to initialise with ASPM
> >> enabled...
> >
> > I have no personal experience with this device; all I know is that the
> > bugzilla suggests that it worked in v5.4, which isn't much help.
> >
> > Possibly the apparent regression was really a .config change, i.e.,
> > CONFIG_PCIEASPM was disabled in the v5.4 kernel vtolkm@ tested and it
> > "worked" but got enabled later and it started failing?
>
> Yeah, I suspect so. The OpenWrt config disables CONFIG_PCIEASPM by
> default and only turns it on for specific targets. So I guess that it's
> most likely that this has never worked...

FYI, there's a bugzilla for this:

https://bugzilla.kernel.org/show_bug.cgi?id=209833

Rob